Re: [Intel-gfx] [PATCH 2/2] drm/edid: Have cea_db_offsets() zero start/end when the data block collection isn't found

2019-09-10 Thread Jean Delvare
On Tue, 10 Sep 2019 12:48:42 +0300, Ville Syrjälä wrote:
> On Tue, Sep 10, 2019 at 11:46:20AM +0200, Jean Delvare wrote:
> > Hi Ville,
> > 
> > On Mon,  2 Sep 2019 16:15:46 +0300, Ville Syrjala wrote:  
> > > From: Ville Syrjälä 
> > > 
> > > Let's make cea_db_offsets() a bit more convenient to use by
> > > setting the start/end offsets to zero whenever the data block
> > > collection isn't present. This makes it safe for the caller
> > > to blindly iterate the data blocks even if there are none.
> > > 
> > > Cc: Jean Delvare 
> > > Signed-off-by: Ville Syrjälä 
> > > ---
> > >  drivers/gpu/drm/drm_edid.c | 8 
> > >  1 file changed, 4 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > > index 7b3072fc550b..e5905dc764c1 100644
> > > --- a/drivers/gpu/drm/drm_edid.c
> > > +++ b/drivers/gpu/drm/drm_edid.c
> > > @@ -3690,6 +3690,9 @@ cea_revision(const u8 *cea)
> > >  static int
> > >  cea_db_offsets(const u8 *cea, int *start, int *end)
> > >  {
> > > + *start = 0;
> > > + *end = 0;
> > > +
> > >   if (cea_revision(cea) < 3)
> > >   return -ENOTSUPP;
> > >  
> > > @@ -4116,10 +4119,7 @@ static void drm_edid_to_eld(struct drm_connector 
> > > *connector, struct edid *edid)
> > >   if (cea_revision(cea) >= 3) {
> > >   int i, start, end;
> > >  
> > > - if (cea_db_offsets(cea, , )) {
> > > - start = 0;
> > > - end = 0;
> > > - }
> > > + cea_db_offsets(cea, , );
> > >  
> > >   for_each_cea_db(cea, i, start, end) {
> > >   db = [i];  
> > 
> > Not sure if that's really needed. As it stands there's only one
> > function which wants to continue after cea_db_offsets() fails, all
> > others just bail out at that point. Now that cea_db_offsets() checks
> > for revision >= 3, the construct above could simply become:
> > 
> > int i, start, end;
> > 
> > if (cea_db_offsets(cea, , ) == 0) {
> > for_each_cea_db(cea, i, start, end) {
> > db = [i];
> > 
> > which is IMHO more elegant and does not require zeroing start and end
> > in cea_db_offsets().  
> 
> I dislike indentation.

It would be the same as currently, so it's not that bad. But well I'm
not maintaining that piece of code so it's not my call anyway.

> Also could perhaps even move the cea_db_offsets()
> into the for_each_cea_db() macro so that the caller doesn't have to care
> about these mundane details at all.

If the macro stays readable, why not.

-- 
Jean Delvare
SUSE L3 Support
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Re: [Intel-gfx] [PATCH 2/2] drm/edid: Have cea_db_offsets() zero start/end when the data block collection isn't found

2019-09-10 Thread Ville Syrjälä
On Tue, Sep 10, 2019 at 11:46:20AM +0200, Jean Delvare wrote:
> Hi Ville,
> 
> On Mon,  2 Sep 2019 16:15:46 +0300, Ville Syrjala wrote:
> > From: Ville Syrjälä 
> > 
> > Let's make cea_db_offsets() a bit more convenient to use by
> > setting the start/end offsets to zero whenever the data block
> > collection isn't present. This makes it safe for the caller
> > to blindly iterate the data blocks even if there are none.
> > 
> > Cc: Jean Delvare 
> > Signed-off-by: Ville Syrjälä 
> > ---
> >  drivers/gpu/drm/drm_edid.c | 8 
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > index 7b3072fc550b..e5905dc764c1 100644
> > --- a/drivers/gpu/drm/drm_edid.c
> > +++ b/drivers/gpu/drm/drm_edid.c
> > @@ -3690,6 +3690,9 @@ cea_revision(const u8 *cea)
> >  static int
> >  cea_db_offsets(const u8 *cea, int *start, int *end)
> >  {
> > +   *start = 0;
> > +   *end = 0;
> > +
> > if (cea_revision(cea) < 3)
> > return -ENOTSUPP;
> >  
> > @@ -4116,10 +4119,7 @@ static void drm_edid_to_eld(struct drm_connector 
> > *connector, struct edid *edid)
> > if (cea_revision(cea) >= 3) {
> > int i, start, end;
> >  
> > -   if (cea_db_offsets(cea, , )) {
> > -   start = 0;
> > -   end = 0;
> > -   }
> > +   cea_db_offsets(cea, , );
> >  
> > for_each_cea_db(cea, i, start, end) {
> > db = [i];
> 
> Not sure if that's really needed. As it stands there's only one
> function which wants to continue after cea_db_offsets() fails, all
> others just bail out at that point. Now that cea_db_offsets() checks
> for revision >= 3, the construct above could simply become:
> 
>   int i, start, end;
> 
>   if (cea_db_offsets(cea, , ) == 0) {
>   for_each_cea_db(cea, i, start, end) {
>   db = [i];
> 
> which is IMHO more elegant and does not require zeroing start and end
> in cea_db_offsets().

I dislike indentation. Also could perhaps even move the cea_db_offsets()
into the for_each_cea_db() macro so that the caller doesn't have to care
about these mundane details at all.

-- 
Ville Syrjälä
Intel
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Re: [Intel-gfx] [PATCH 2/2] drm/edid: Have cea_db_offsets() zero start/end when the data block collection isn't found

2019-09-10 Thread Jean Delvare
Hi Ville,

On Mon,  2 Sep 2019 16:15:46 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä 
> 
> Let's make cea_db_offsets() a bit more convenient to use by
> setting the start/end offsets to zero whenever the data block
> collection isn't present. This makes it safe for the caller
> to blindly iterate the data blocks even if there are none.
> 
> Cc: Jean Delvare 
> Signed-off-by: Ville Syrjälä 
> ---
>  drivers/gpu/drm/drm_edid.c | 8 
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 7b3072fc550b..e5905dc764c1 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3690,6 +3690,9 @@ cea_revision(const u8 *cea)
>  static int
>  cea_db_offsets(const u8 *cea, int *start, int *end)
>  {
> + *start = 0;
> + *end = 0;
> +
>   if (cea_revision(cea) < 3)
>   return -ENOTSUPP;
>  
> @@ -4116,10 +4119,7 @@ static void drm_edid_to_eld(struct drm_connector 
> *connector, struct edid *edid)
>   if (cea_revision(cea) >= 3) {
>   int i, start, end;
>  
> - if (cea_db_offsets(cea, , )) {
> - start = 0;
> - end = 0;
> - }
> + cea_db_offsets(cea, , );
>  
>   for_each_cea_db(cea, i, start, end) {
>   db = [i];

Not sure if that's really needed. As it stands there's only one
function which wants to continue after cea_db_offsets() fails, all
others just bail out at that point. Now that cea_db_offsets() checks
for revision >= 3, the construct above could simply become:

int i, start, end;

if (cea_db_offsets(cea, , ) == 0) {
for_each_cea_db(cea, i, start, end) {
db = [i];

which is IMHO more elegant and does not require zeroing start and end
in cea_db_offsets().

-- 
Jean Delvare
SUSE L3 Support
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